Concentration of sulfid ores.



HENRY LAVERS, CAMBERWELL, ALFRED HENRY PIPER LOWRY, OFPRAHRAN, AND HENRYHOWARD GREENWAY, OF MELBOURNE, VICTORIA, AUSTRALIA, ASSIGNORS, BY MESNJEASSIGNMENTS, T MINERALS SEPARATION AMERICAN SYNDICATE'(1913) rirmrrnii,or LONDON, ENGLAND.

CONCENTRATION OF SULFIJD'ORES.

subject of the King of England, residing at 'Camberwell VictoriaAustralia ALFRED HENRY PIPER LOWRY, a subject of the King of- England,and residing at Lynzala, High street, Prahran, State ofVictoria,Australia,

and HENRY HOWARD GREENWAY, a subject of the King of England, residing atMelbourne, Victoria, Australia, have invented certain new and'usefulImprovements in the Concentration of Sulfid Ores, of which the followingis a specification.

This invention relates to certain improvements in the concentration ofsulfid ores, and refers more especially to the concentration of mixedzinc and lead sulfid ores, that is to say ores containing a mixture ofgalena and blende with gangue. In this specification the term ores isintended to include concentrates, tailings, slimes, and other productscontaining metallic sulfids.

This invention rel-ates to the concentration of sulfid ores by flotationseparation, and more especially to froth flotation separation, in whicha froth of sulfids is floated to the surface consequent upon theaeration or' agitation of the ores in the presence of a suitablefrothing agent (such as an essential oilfor instanceeucalyptus oil).

Hitherto froth flotation separation of the mixed sulfids from the ganguehas generally been conducted withthe addition of acid to the circuitwater. With certain ores known as calcitic orescontaining carbonates theconsumption of acid has in some instances largely added to the cost oftreatment. This applies especially to slimes, as the acid consumingsubstances (such as calcite, &c.) are mostly found with the finelydivided slimes. An alkaline medium or circuit water has been adopted insome cases, and, under certain conditions, for the differential orpreferential flotation separation of certain sulfids from other sulfids,but so far as we are aware, a flotation separation of mixed sulfidsgenerally from the gangue has not been effected with the employment insolution in the pulp of an alkaline selectivity-modifying agent. It haspreviously been proposed to eflect the concentration of copper ores bythe agitation froth process by agitating the ore sus- Specification ofLetters Patent.

' ture.

Patented nee. i2, rare.

Application filed March 14, 1914. Serial No. 824,765.

pended in Water with a minute quantity of an aromatic hydroxy compoundto beat in air and form a froth, at the same time adding to the circuitsolution a small proportion of an alkali to facilitate the solution ofthe aromatic hydroxy compound employed as a frothing agent.

We have discovered that if a finely pulverized ore is submitted toflotation separation with agitation and aeration and with a suitablefrothing agent (such as an essen tial oil, for instance eucalyptus oil)in Water containmg in solution an alkaline substance,

cient to insure the formation of a mineral bearing froth.

"such as carbonate of soda, a froth of the metallic sulfids will riseto. the surface and The question as to whether in the treatment of anyparticular ore in a certain circuit water the addition of an organicfrothing agent is necessary can be determined by a simple laboratorytest.

If desired the resultant products may be retreated with or without theaddition of fresh quantities of the substances referred to.

As an example of the application of this process We may mention certainexperiments which have been conducted by us A. One pound of slimesassaying 14.4% lead, and 14.6% zinc, was submitted to flotationseparation with agitation and aeration in l lbs. of water containing insolution carbonate of soda equivalent to 224 lbs. per ton of slimestreated, to which was also added eucalyptus oil equivalent to 0.6 lbs.per ton of slimes. The charge was thoroughly aerated by being agitatedin such a way as to disseminate air through the mix- On bringing themixture torest, a froth of mixed concentrates was obtained assaying 26%lead, and 29.8% zinc, leaving a residue assaying lead, and 2.2% zinc.

B. A parcel containing one ton of slimes from Broken Hill assaying 11%lead and ing agitated in about four (4) tons of water contain'ing'anamount of soda ash equivalent to 35 lbs. per ton of ore treated, andeucalyptus oil equivalent to three-quarters (if) of a lb. per ton of oretreated at a temperature of from 125 to 130 F. A froth of mixed sulfidswas Obtained assaying- 18.5% lead and 27.4% zinc, being a recovery of90% lead and 94% zinc- These float concentrates were retreated withsmall additions of eucalyptus oil and soda ash to the circuit Waterequivalent to 0.1 lbs. and

.4 lbs. respectively per ton of ore treated while. the temperature wasmaintained at about 125 to 130 F., when a fr h of mixed sulfids wasobtained assaying 2.4% lead and 35.8% "zinc, being a recovery of 84.3%lead and 90% zinc.

0. Two lbs. of Broken Hill slimes were mixed with 7 lbs. water at 130F., and soda ash equal to.22.4 lbs. per ton of the slimes. The mixturewas then thoroughly aerated by being agitated, with the result that amixed concentrate assaying 29.5% lead, 35.2% zinc, 25.0 ozs. per tonsilver was produced, giving recoveries of 90.0% lead, 92.7% zinc, and91.5% silver. In this test -no frothing agent other than soda ash wasadded. I

D. Two lbs. of Queensland copper ore tarnished by weathering andunsuitable for ordinary flotation treatment assaying 2.9% copper (of,which 0.5% copper was oxidi zed) 6.5 dwts. per ton gold were mixed with7 lbs. water at F. containing soda ash equal to 33.6 lbs; per ton of theore and a mixture of about equal proportions of eucalyptus oil andmineral oil equivalent to 2 lbs. per ton of ore. The whole was thenthoroughly aerated by bein agitated with the result that a froth ofmixed sulfids was obtained assaying 11.3% copper, 26.1 dwts. gold, beinga recovery of 74.4% copper, 76.7% gold.

The concentrates obtained by this invention are found to be in a mostsuitable condition for preferential flotation separation of one of thesulfids from the other sulfids by one of the known methods, moreespecially one employing an alkaline separating medium. Though it hasbeen found that the above method is especially applicable to thetreatment of slimes, it is not confined to the treatment of that classof ore,but is applicable to coarser material also.

This method of, treatment is especially applicable to cases where byreason of the state of the ore due to oxidation by exposure orweathering (such as accumulated dump slimes and tarnished ores), the useof acid is inadvisable, and neutral'circuit water is unsuitable.

The alkaline substances most suitable for addition to the circuit waterare the carbonates of the alkaline metals, but other alkalis maybe'used. We prefer in most cases the crude sodium carbonate or soda ash.The amount of alkaline substance added to the circuit water should inall cases be sufliamount of soaps which tend to form an indiscriminatefroth of sulfids and gangue. We therefore prefer to use a frothing agentother than a fatty'acid.

In the following claims the terms substantially all the floatablemetalliferous minerals and substantially all the floatable zinc and leadare intended to mean such a recovery of metalliferous mineral or of zincand lead together as is practically obtainable in a procedure which aimsto float all the metalliferous mineral as differentiated frompreferential selection of one metalliferous mineral from another.

What we claim as our invention and desire to secure by Letters Patentis 1. A process of concentrating ores con: taining mixed metalliferousminerals which consists in agitating and aerating a pulp of such an ore,such pulp containing 1n solution an alkaline selectivity-modifyingagent, so as to obtain a froth of concentrates of substantially allthefloatable metalliferous minerals while the gangue sinks, saidsolution being alkaline during separation of the minerals, andseparating the froth, whereby the metalliferous minerals are separatedfrom the gangue.

2. A process of concentrating ores containingmixed metalliferousminerals which consists in agitating and aerating a pulp of such an ore,such pulp containing in solution an alkaline selectivity-modifying agentand also containing a small proportion of a frothing agent, so as toobtain a froth of concentrates of substantially all the floatablemetalliferous minerals while the gangue sinks, said solution beingalkaline during separation of the minerals, and separating thefrotlnwhereby the metalliferous mineralsare separated from the gangue.

3. A process ofconcentrating ores containing mixed metalliferousminerals which consists inagitating and aerating a pulp of such an ore,such pulp. contalnlng in solu minerals, and separating the froth,whereby the metalliferous minerals are separated from the gangue.

4. A process of concentrating ores containing mixed metalliferousminerals which consists in agitating and aerating a pulp of such an ore,such pulp containing in solu-- tion a carbonate of an alkaline metal andalso containing a small proportion of a frothing agent, so as to obtaina froth of concentrates of substantially all the floatablen'ietalliferous minerals while the gangue sinks, said solution beingalkaline during' separation of the minerals, and separating the froth,whereby the metalliferous mineralsare separated from the gangue.

5. A process of concentrating ores containing mixed metalliferousminerals which consists in agitating and aerating a pulp of such an ore,such pulp containing sodium carbonate in solution so as to obtain afroth of concentrates of substantiallyallthe float while the ganguesinks, said solution being alkaline during separation of the minerals,and separating thefroth, whereby the metalliferous minerals areseparated from the gangue. p

7. A process of concentrating zinc-lead ores which consists in agitatingand aerating a pulp of such an ore, such pulp containing in solution analkaline selectivity-modifying agent, so as to obtain a froth ofconcentrates containing substahtially all the floatable zinc and leadwhile the gangue sinks, said solution being alkaline during theseparation of the minerals, and separating the froth, whereby the zincand lead are separated from the gangue.

8. A process of concentrating zine-lead ores which consists in agitatingand aerating a pulp of such an ore, such pulp containing in solution analkaline selectivity-modifying agent and also containing a smallproportion of a frothing agent, so as to obtain a froth of concentratescontaining substantially all the floa'table zinc and lead while thegangue sinks, said solution being-alka line during separation of theminerals, and

separatingthe froth, whereby the zinc and lead are separated from thegangue.

9. A process of concentrating zinc-lead ores which consists in agitatingand aerating a pulp of such an ore, such pulp containing in solution acarbonate of an alkaline metal, so as to obtain a froth of concentratescontaining substantially all the fioatable zinc and lead while thegangue sinks, said solution being alkaline during separation of theminerals, and separating the froth, whereby the zinc and lead areseparated from the gangue.

' 10. A process-of concentrating zinc-lead ores which consists inagitating and aerating the pulp of such an ore, such pulp containing insolution a carbonate of an alkaline metal and also containing a smallproportion of a frothing agent, so as to obtain a froth of concentratescontaining substantially all the floatable zinc and lead while thegangue sinks, said solution being alkaline during separation of theminerals, and separating the froth, whereby the zinc and lead areseparated from the gangue.

11. A process of concentrating zinc-lead ores which consistsin agitatingand aerating a pulp of such an ore, such pulp containing sodiumcarbonate in solution, so as to obtain a froth of concentratescontaining substantially all the floatable zinc and 'lead while thegangue sinks, said solution being alkaline during separation of theminerals, and separating the froth, whereby the zinc and lead areseparated from the gangue.

12. A process of concentrating Zinc-lead- "ores which consists 1nagltating and aeratingv a pulp of such an ore, such pulp containingsodium carbonate in solutiorr and also containing a small proportion ofa frothing" agent, so as to obtain a froth of concentrates containingsubstantially all the floatable zinc and lead while the gangue sinks,said solution being alkaline during separation of the minerals, andseparating the froth,

whereby the zinc and lead are separated

